/*
 * Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <memory>
#include <vector>
#ifdef PADDLE_WITH_CUDA
#include <cuda_runtime.h>
#endif

#include "ext_dll_decl.h"  // NOLINT
#include "ext_dtype.h"     // NOLINT
#include "ext_place.h"     // NOLINT

namespace paddle {
namespace framework {
class CustomTensorUtils;
}  // namespace framework

class StreamWrapper {
 public:
  StreamWrapper() : stream_(nullptr), is_stream_set_(false) {}
  void SetStream(void* stream) {
    stream_ = stream;
    is_stream_set_ = true;
  }

  void* GetStream() const { return stream_; }

  bool IsStreamSet() const { return is_stream_set_; }

 private:
  //  cudaStream_t stream_;
  void* stream_;
  bool is_stream_set_;
};

class PD_DLL_DECL Tensor {
 public:
  /// \brief Construct a Tensor on target Place for CustomOp.
  /// Generally it's only used for user to create Tensor.
  explicit Tensor(const PlaceType& place);
  /// \brief Reset the shape of the tensor.
  /// Generally it's only used for the input tensor.
  /// Reshape must be called before calling
  /// mutable_data() or copy_to(const PlaceType& place)
  /// \param shape The shape to set.
  void reshape(const std::vector<int64_t>& shape);

  /// \brief Get the memory pointer in CPU or GPU with
  /// specific data type.
  /// Please Reshape the tensor first before call this.
  /// It's usually used to get input data pointer.
  /// \param place The place of the tensor this will
  /// override the original place of current tensor.
  template <typename T>
  T* mutable_data(const PlaceType& place);

  /// \brief Get the memory pointer in CPU or GPU with
  /// specific data type. Please Reshape the tensor
  /// first before call this.It's usually used to get
  /// input data pointer.
  template <typename T>
  T* mutable_data();

  /// \brief Get the memory pointer directly.
  /// It's usually used to get the output data pointer.
  /// \return The tensor data buffer pointer.
  template <typename T>
  T* data() const;

  /// \brief Copy the host memory to tensor data.
  /// It's usually used to set the input tensor data.
  /// \param PlaceType of target place, of which
  /// the tensor will copy to.

  template <typename T>
  Tensor copy_to(const PlaceType& place) const;

  /// \brief Return the shape of the Tensor.
  std::vector<int64_t> shape() const;

  /// \brief Return the data type of the tensor.
  /// It's usually used to get the output tensor data type.
  /// \return The data type of the tensor.
  DataType type() const;

  /// \brief Get the size of current tensor.
  /// Use this method to get the size of tensor
  /// \return int64_t.
  int64_t size() const;

  /// \brief Get the place of current tensor.
  /// Use this method to get the place of tensor
  /// \return Place.
  const PlaceType& place() const;

  /// \brief Cast datatype from one to another
  Tensor cast(const DataType& target_type) const;

#ifdef PADDLE_WITH_CUDA
  /// \bref Get current stream of Tensor
  cudaStream_t stream() const;
#endif

 private:
  friend class framework::CustomTensorUtils;
  mutable std::shared_ptr<void> tensor_;
  mutable PlaceType place_;
  StreamWrapper stream_;
};

}  // namespace paddle
